This invention relates to materials useful as magnetic head sliders.
The most advanced material used to afford a magnetic circuit in a magnetic head for high density recording is a Permalloy thin film having a high permeability. The slider materials generally combined with such magnetic heads are ceramic materials. The slider materials are required to exhibit good CS/S (contact start/stop) properties or wear resistance of the sliding surface of a slider, a dense structure, a high hardness, and improved processability in various steps including cutting, grooving, and mirror finishing. Sintered bodies of alumina-titanium carbide (Al.sub.2 O.sub.3 -TiC) are known to meet such requirements.
For example, Japanese Patent Application Kokai No. 55-163665 discloses a sintered body prepared by hot pressing a mixture of alumina and titanium carbide. This sintered body found a use as a slider element of a floating magnetic head. Another sintered body is disclosed in Japanese Patent Application Kokai No. 56-140066 and it is prepared by adding yttrium in the form of yttrium oxide (or as a component of a solid solution or composite material in some cases) or yttrium carbide (or as a component of a double carbide or composite material in some cases) to alumina and titanium carbide followed by hot isostatic pressing (HIP). A further sintered body is disclosed in Japanese Patent Application Kokai No. 57-135772 and it is prepared by adding Y.sub.2 O.sub.3 and at least one machinability-improving agent selected from MgO, NiO, Cr.sub.2 O.sub.3, and ZrO.sub.2 to a mixture of Al.sub.2 O.sub.3, TiC and TiO.sub.2, followed by HIP. Also known is a method for obtaining a sintered alumina-titanium carbide body by adding molybdenum (Mo) or tungsten (W) in elemental or carbide form to an alumina-titanium carbide mixture followed by sintering.
The sintered Al.sub.2 O.sub.3 -TiC bodies obtained by these methods, however, suffer from some problems in machinability or processability in that they tend to undergo frequent chipping and grain release at an increased cutting speed and they also tend to release grains during mirror finishing. In order to reduce chipping frequency, an Fe group metal in elemental or oxide form is added to a starting material from which a sintered ceramic body for ceramic tools is made. The resulting sintered bodies cease to be non-magnetic and are thus undesirable for use as magnetic head slider material.
There is the continuing need for the development of a sintered alumina-titanium carbide body free of such problems.